Joyce from Stellar here. Prof. David Mazieres is creating a new provably-correct version of the consensus system and will be publishing a white paper that will be in line with his normal, rigorous academic standards.

In addition, Graydon Hoare (creator of Rust) has also joined the Stellar team from Mozilla. Now that Stellar supports over 2.3 million wallets, making it the largest implementation of this system, we have found certain scaling limitations of the core tech. Graydon is one of the developers spearheading efforts to make Stellar capable of scaling well beyond its current limitations.

Once these two efforts are complete in a few months, I think you will feel much more comfortable with the robustness of the Stellar protocol.